Question

A. 5x + 2y = -3
7x + 8y = 1

b. 3x - 2y = 12
5x + y = 7

Tentukan hasil x dan y dengan menggunakan metode subtitusi! bantu jawaab plis..

Answer 1

A. 5x + 2y = -3
5x = -3 -2y
x = -3 - 2y /5
 
7x + 8y = 1
7 ( -3 - 2y / 5 ) + 8y = 1
7 (-3 -2y ) + 40 y = 5
- 21 -14y + 40y =5
26y = 26
y = 1

5x + 2y = -3
5x + 2( 1) = -3
5x = -3 - 2
x = -1


b.3x - 2y = 12
3x = 12 + 2y
x= 12 + 2y / 3

5x + y = 7
5 ( 12 + 2y / 3 )+ y = 7
5(12+2y) + 3y =21
60 + 10y + 3y = 21
13y = 39
y = 3

3x - 2(3) = 12
3x -6 =12
3x=6
x=2